Abstract
The use of high pressure and high temperature conditions is essential in the preparation of silicon clathrate compounds with electron excess compositions and related Si-rich binary compounds. The preparation conditions and crystal structures of Ba8Si46, Ba24Si100, BaSi6, LaSi5, LaSi10, NaxSi136 (x>24) and related Zintl silicides are discussed. These are the systems rich in superconductors.